Despite good performances from Kerry Godliman and Karl Pilkington, the first full series of this care home comedy is another slushy mess, says Jack Seale

It's almost a year since the pilot episode of Derek, Ricky Gervais's controversial comedy in which he plays a man, who appears to have learning difficulties, finding fulfilment working in a care home for the elderly.

How much impact the mixed reviews had, we don't know. Some tweaks are noticeable. But if anything, the new episodes (I've seen the first two) are worse, because the fundamental problems have got worse. Gervais, left alone without a co-writer or anyone to say no to him, has an impatient, button-pushing approach to drama, an increasingly wide sentimental streak and a weakness for jarring misjudgements. They make Derek a curdled pudding of a show.

Derek is no longer clearly the main character. The excellent Kerry Godliman shares that burden as Hannah, the kindly care home manager, as the focus shifts from how touching it is when a vulnerable, kind man struggles to exist in an unforgiving world, to how moving it is when old people end up in a municipal home, forgotten by society and sustained by selfless carers.

Most writers would try to find a new angle on this, or at least put an engaging story on top so the moral can sneak up unnoticed. Not Gervais. Through laziness or ineptitude, he just hammers it. The obvious plot device of the home being threatened by council budget cuts is slapped out in episode one, leaving Godliman to make the best of some horribly patronising lines as Hannah heroically pledges to save the place herself, patiently explaining to the audience why it's bad if old people's homes close.

To underline the point, between scenes – where The Office would have a discreet shot of a printer whirring – there are slow pans across old people in their chairs, accompanied by the plangent piano muzak that blighted the pilot but is smeared even more thickly all over this. Derek often feels like the start of a daytime TV ad for over-60s life insurance. The old folk hardly have any lines. They're symbols. Extras.

Worse than that, in episode two the elderly are magic. A gum-chewing teen reluctantly slouches in, to work off her community service. One encouraging remark from a nameless old woman and the girl is saved, converted to a motivated philanthropist with a new sense of her own worth.

By far the best character, in script and performance, is Dougie the caretaker, played by Karl Pilkington. Potentially he's a comic original, a man with an absurd, hopeless existence who is free of delusion. From the gutter, he questions whether anyone else is really doing better. Pilkington nails Dougie's mix of despair and defiance – he could be explored and deepened as the series goes on.

You wouldn't bet on Gervais to do it, though. Things like character development have to be sacrificed when you're this desperate to make a point. When the pilot went out, Gervais stressed that Derek does not have "learning difficulties" or any other definitive frailty that might raise awkward questions about how accurate or sensitive Gervais's performance is. Now he bluntly addresses his critics by including a scene where the evil council bean-counter asks Derek if he's been tested for autism. Derek responds by wondering whether a positive result would lead to invasive treatment, or experiments. No. Would it change who he is or what he does? The man says no. Derek walks off.

The message: people who put labels on those who are different are missing the point, cramping their unique style. This is where Gervais's naïve easy answers become offensive, even if there's no bad-taste laughter at Derek's expense, and none of the pratfalling Derek suffered in the pilot. To make life easier for himself, Gervais is shrugging his shoulders and refusing to accept that Derek is anything other than pure and kind, when he very clearly has problems that in reality would be an awful lot of worry and work. Try telling the parents of an autistic child that precise diagnoses are unhelpful.

A co-writer or strong producer might have pointed out how misguided this scene is. They might observe that using the old people as emotional bait is empty and mawkish. They'd surely balk at the handbrake shifts of tone brought by David Earl as Kev, Derek's priapic, Special Brew-swilling slob of a friend, who is ludicrously overcooked and seems to act as a safety net: even in a tender comedy drama about death and loneliness, there's still someone there to get a cheap laugh.

However bad Derek gets – and when it's really bad it will make you do a full-on Munch Scream face at your telly – the memory of the restrained, clear-thinking perfection of The Office still lingers. That talent could still be in there. But Ricky Gervais won't rediscover it until he puts down that giant foam mallet and picks up a pen.